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smf_method(5) [sunos man page]

smf_method(5)						Standards, Environments, and Macros					     smf_method(5)

smf_method - service management framework conventions for methods DESCRIPTION
The class of services managed by svc.startd(1M) in the service management framework, smf(5), consists of applications that fit a simple fork(2)-exec(2) model. The svc.startd(1M) master daemon and other restarters support the fork(2)-exec(2) model, potentially with additional capabilities. The svc.startd(1M) daemon and other restarters require that the methods which activate, manipulate, or examine a service instance follow the conventions described in this manual page. Invocation form The form of a method invocation is not dictated by convention. In some cases, a method invocation might consist of the direct invocation of the daemon or other binary executable that provides the service. For cases in which an executable script or other mediating executable is used, the convention recommends the form: /path/to/method_executable abbr_method_name The abbr_method_name used for the recommended form is a supported method such as start or stop. The set of methods supported by a restarter is given on the related restarter page. The svc.startd(1M) daemon supports start, stop, and refresh methods. A restarter might define other kinds of methods beyond those referenced in this page. The conventions surrounding such extensions are defined by the restarter and might not be identical to those given here. Environment Variables The restarter provides three environment variables to the method that determine the context in which the method is invoked. SMF_FMRI The service fault management resource identifier (FMRI) of the instance for which the method is invoked. SMF_METHOD The full method name of the method that is invoked SMF_RESTARTER The service FMRI of the restarter that invokes the method These variables should be removed from the environment prior to the invocation of any persistent process by the method. A convenience shell function, smf_clear_env, is given for service authors who use Bourne-compatible shell scripting to compose service methods in the include file described below. The method context may cause other environment variables to be set as described below. Method Tokens A set of tokens are parsed and expanded with appropriate values from the method invocation by the restarter svc.startd. Other restarters might not support method tokens. The delegated restarter for inet services, inetd(1M), does not support the following method expansions. %% % %r Name of the restarter, such as svc.startd %m Name of the method, such as start or stop %s Name of the service %i Name of the instance %f FMRI of the instance %{prop[:,]} Value(s) of a property. The prop might be a property FMRI, a property group name and a property name separated by a /, or a property name in the application property group. These values can be followed by a , (comma) or : (colon). If present, the separators are used to separate multiple values. If absent, a space is used. The following shell metacharacters encoun- tered in string values are quoted with a (backslash): ; & ( ) | ^ < > newline space tab " ' An invalid expansion constitutes method failure. Two explicit tokens can be used in the place of method commands. :kill [-signal] Sends the specified signal, which is SIGTERM by default, to all processes in the primary instance contract. Always returns SMF_EXIT_OK. This token should be used to replace common pkill invocations. :true Always returns SMF_EXIT_OK. This token should be used for methods that are required by the restarter but which are unneces- sary for the particular service implementation. Exiting and Exit Status The required behavior of a start method is to delay exiting until the service instance is ready to answer requests or is otherwise func- tional. The following exit status codes are defined in <libscf.h> and in the shell support file. SMF_EXIT_OK 0 Method exited, performing its operation successfully. SMF_EXIT_ERR_FATAL 95 Method failed fatally and is unrecoverable without admin- istrative intervention. SMF_EXIT_ERR_CONFIG 96 Unrecoverable configuration error. A common condition that returns this exit status is the absence of required configuration files for an enabled service instance. SMF_EXIT_MON_DEGRADE 97 Monitor assesses service instance as operating in a degraded mode. SMF_EXIT_MON_OFFLINE 98 Monitor assesses service instance as non-responsive and effectively offline. SMF_EXIT_ERR_NOSMF 99 Method has been mistakenly invoked outside the smf(5) facility. Services that depend on smf(5) capabilities should exit with this status value. SMF_EXIT_ERR_PERM 100 Method requires a form of permission such as file access, privilege, authoriza- tion, or other credential that is not available when invoked. SMF_EXIT_ERR_OTHER non-zero Any non-zero exit status from a method is treated as an unknown error. A series of unknown errors can be diag- nosed as a fault by the restarter or on behalf of the restarter. Use of a precise exit code allows the responsible restarter to categorize an error response as likely to be intermittent and worth pursuing restart or permanent and request administrative intervention. Timeouts Each method can have an independent timeout, given in seconds. The choice of a particular timeout should be based on site expectations for detecting a method failure due to non-responsiveness. Sites with replicated filesystems or other failover resources can elect to lengthen method timeouts from the default. Sites with no remote resources can elect to shorten the timeouts. Method timeout is specified by the timeout_seconds property. Shell Programming Support A set of environment variables that define the above exit status values is provided with convenience shell functions in the file /lib/svc/share/ This file is a Bourne shell script suitable for inclusion via the source operator in any Bourne-compatible shell. To assist in the composition of scripts that can serve as SMF methods as well as /etc/init.d scripts, the smf_present() shell function is provided. If the smf(5) facility is not available, smf_present() returns a non-zero exit status. One possible structure for such a script follows: if smf_present; then # Shell code to run application as managed service .... smf_clear_env else # Shell code to run application as /etc/init.d script .... fi This example shows the use of both convenience functions that are provided. Method Context The service management facility offers a common mechanism set the context in which the fork(2)-exec(2) model services execute. The desired method context should be provided by the service developer. All service instances should run with the lowest level of privi- leges possible to limit potential security compromises. A method context may contain the following properties: use_profile A boolean that specifies whether the profile should be used instead of the user, group, privileges, and limit_priv- ileges properties. environment Environment variables to insert into the environment of the method, in the form of a number of NAME=value strings. profile The name of an RBAC (role-based access control) profile which, along with the method executable, identifies an entry in exec_attr(4). user The user ID in numeric or text form. group The group ID in numeric or text form. supp_groups An optional string that specifies the supplemental group memberships by ID, in numeric or text form. privileges An optional string specifying the privilege set as defined in privileges(5). limit_privileges An optional string specifying the limit privilege set as defined in privileges(5). working_directory The home directory from which to launch the method. :home can be used as a token to indicate the home directory of the user whose uid will be used to launch the method. If the property is unset, :home is used. corefile_pattern An optional string that specifies the corefile pattern to use for the service, as per coreadm(1M). Most restarters supply a default. Setting this property overrides local customizations to the global core pattern. project The project ID in numeric or text form. :default can be used as a token to indicate a project identified by getde- faultproj(3PROJECT) for the user whose uid is used to launch the method. resource_pool The resource pool name on which to launch the method. :default can be used as a token to indicate the pool speci- fied in the project(4) entry given in the project attribute above. The method context can be set for the entire service instance by specifying a method_context property group for the service or instance. A method might override the instance method context by providing the method context properties on the method property group. Invalid method context settings always lead to failure of the method, with the exception of invalid environment variables that issue warn- ings. In addition to the context defined above, many fork(2)-exec(2) model restarters also use the following conventions when invoking executa- bles as methods: Argument array The arguments in argv[] are set consistently with the result /bin/sh -c of the exec string. File descriptors File descriptor 0 is /dev/null. File descriptors 1 and 2 are recommended to be a per-service log file. FILES
/lib/svc/share/ Definitions of exit status values. /usr/include/libscf.h Definitions of exit status codes. SEE ALSO
coreadm(1M), inetd(1M), svccfg(1M), svc.startd(1M), exec(2), fork(2), getdefaultproj(3PROJECT), exec_attr(4), project(4), service_bun- dle(4), attributes(5), privileges(5), rbac(5), smf(5), smf_bootstrap(5) NOTES
The present version of smf(5) does not support multiple repositories. SunOS 5.10 2 Dec 2004 smf_method(5)
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